Self-limiting electrosurgical return electrode

Abstract

A self-limiting electrosurgical return electrode for use with electrosurgery. Through the selection of impedance characteristics for the electrode materials of the principal body of the electrode, and through tailoring of electrode geometries, the return electrode of the present invention is self-regulating and self-limiting as to current density and temperature rise so as to prevent patient trauma. The electrosurgical return electrode includes a sheet of material having an effective bulk impedance equal to or greater than about 4,000 OMEGA.cm and one or more connectors for making electrical connection to the sheet. The effective bulk impedance of the sheet may arise from resistive components, capacitive components, inductive components, or combinations thereof. The configuration of the presently described return electrode allows the electrode to self-limit the electrode's current densities, thereby preventing burning of a patient during surgery. Furthermore, through employment of washable surface areas, the electrode is made readily cleanable, disinfectable, sterilizable, and reusable. An optional sleeve is provided for cooperative use with the electrode.

Description

1. The Field of the InventionThis invention relates to electrosurgery and, more particularly, to return electrodes that are adapted for providing effective and safe electrosurgical energy return without conducting or dielectric gels, which may be reusable and / or disposable.2. The Relevant TechnologyAs is known to those skilled in the art, modern surgical techniques typically employ radio frequency (RF) power to cut tissue and coagulate bleeding encountered in performing surgical procedures. For historical perspective and details of such techniques, reference is made to U.S. Pat. No. 4,936,842, issued to D'Amelio et al., and entitled "Electroprobe Apparatus," the disclosure of which is incorporated by this reference.As is known to those skilled in the medical arts, electrosurgery is widely used and offers many advantages including the use of a single surgical tool for both cutting and coagulation. Every monopolar electrosurgical generator system must have an active electrode which is...

AI Technical Summary

Benefits of technology

The present invention overcomes the problems of the prior art by providing a return electrode that eliminates patient burns without the need for expensive disposable electrodes and monitoring circuits in specialized RF generators.

It can be appreciated that I.sub.max may vary from patient to patient due to changes in the amount of time that the electrode is in contact with the patient, the electrical characteristics of the patient's skin (i.e., resistivity, and the like), the amount of heat being conducted by the patient, the patients initial skin temperature, and the like. With an electrosurgical return electrode designed according to the prior art, in the event that the contact area with the patient reduces below the A.sub.contact(min) while maintaining the I.sub.max, a burn may result because (I / A).sub.critical,>100 mA / cm.sup.2, which is the burn threshold. In contrast, the present invention limits the possibility of a burn caused from a reduction of the contact area below A.sub.contact(min), while also preventing electrosurgical procedures when the contact area is significantly reduced. Therefore, by selecting the appropriate impedance of electrode 60, the current I is always reduced below I.sub.max when A<A.sub.contact(min).

Problems solved by technology

If a relatively high current density is produced at the return electrode, the temperature of the patient's skin and tissue will rise in this area and can result in an undesirable patient burn.

These return electrodes are an improvement over the old steel plates and resulted in fewer patient return electrode burns but have resulted in additional surgical costs in the United States of several tens of millions of dollars each year.

Even with this improvement, hospitals were still experiencing some patient burns caused by electrodes that would accidentally fall off or partially separate from the patient during surgery.

This system has resulted in additional reduction in patient return electrode burns, but requires a special disposable electrode and an added circuit in the generator that drives the cost per procedure even higher.

Fifteen years after this system was first introduced, fewer than 40 percent of all the surgical operations performed in the United States use this system because of its high costs.

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